Mut`ah marriage is a prohibited and invalid kind of marriage. Scholarly consensus settled on prohibiting it, and anyone who regards it as permissible should be told about the reports from the Messenger of Allah (blessings and peace of Allah be upon him) which clearly state that it is prohibited. If he insists on his view on the basis of some specious argument or misinterpretation of the text, then he is misguided and wrong regarding this matter, but he is not to be deemed a disbeliever, and that does not put him beyond the bounds of Islam. Please see the long answer.

According to the correct scholarly opinion, the repentance of one who has apostatised repeatedly is to be accepted, and he comes under the same rulings as any other Muslim.

Seeing the angels and the jinn, in a form other than their true form, is possible. As for suggesting that only children can see that, we do not know of any text which speaks of that. This is a matter of the unseen, and we cannot say anything about it except on the basis of evidence, and there is no evidence to deny or affirm that.

Islamic `Aqidah is not a theoretical and philosophical method; action is an essential part of this `Aqidah. Hence the Ahl As-Sunnah agreed that faith consists of words and deeds, or speaking with the tongue, believing in the heart and acting with the physical faculties. With regard to applying this `Aqidah in real life, this is done by learning it, propagating it, calling others to it, and refuting those who go against it with wisdom and beautiful preaching.